I buy the OH CRAP moment concept myself. But yeah, its not one of those issues that matters much, but part of what I do is honor the original build while paying homage to the different personalities that purchased it and the personal likes/dislikes of this vintage. Since Greg mentioned it, the new plan is to weld just two seams and leave the third floating. I can see a concern for a little flex where the fenders mount. It will still be very tight yet allow for some flex without tearing.
Thanks to everyone for posting. When this truck is finished, since I do all the work myself, I will have many of you to thank for helping unfreeze my brain as I find myself sitting on the fence on a lot of issues.